import socket

s = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
#绑定端口
s.bind(('127.0.0.1',9999))

print('Bind UPD on 9999...')
while True:
    #接受数据
    data,addr = s.recvfrom(1024)
    print('Recevied from %s:%s.' % addr)
    s.sendto(b'Hello,%s!' % data,addr)